1 files changed, 250 insertions, 10 deletions

diff --git a/crates/ra_ide_api/src/diagnostics.rs b/crates/ra_ide_api/src/diagnostics.rs
index 53d95fb4c..d48772225 100644
--- a/crates/ra_ide_api/src/diagnostics.rs
+++ b/crates/ra_ide_api/src/diagnostics.rs
@@ -1,21 +1,20 @@
+use itertools::Itertools;
 use hir::{Problem, source_binder};
 use ra_ide_api_light::Severity;
 use ra_db::SourceDatabase;
+use ra_syntax::{
+    Location, SourceFile, SyntaxKind, TextRange, SyntaxNode,
+    ast::{self, AstNode},
 
-use crate::{Diagnostic, FileId, FileSystemEdit, SourceChange, db::RootDatabase};
+};
+use ra_text_edit::{TextEdit, TextEditBuilder};
+
+use crate::{Diagnostic, FileId, FileSystemEdit, SourceChange, SourceFileEdit, db::RootDatabase};
 
 pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic> {
     let syntax = db.parse(file_id);
 
-    let mut res = ra_ide_api_light::diagnostics(&syntax)
-        .into_iter()
-        .map(|d| Diagnostic {
-            range: d.range,
-            message: d.msg,
-            severity: d.severity,
-            fix: d.fix.map(|fix| SourceChange::from_local_edit(file_id, fix)),
-        })
-        .collect::<Vec<_>>();
+    let mut res = syntax_diagnostics(file_id, &syntax);
     if let Some(m) = source_binder::module_from_file_id(db, file_id) {
         for (name_node, problem) in m.problems(db) {
             let source_root = db.file_source_root(file_id);
@@ -63,3 +62,244 @@ pub(crate) fn diagnostics(db: &RootDatabase, file_id: FileId) -> Vec<Diagnostic>
     };
     res
 }
+
+fn syntax_diagnostics(file_id: FileId, file: &SourceFile) -> Vec<Diagnostic> {
+    fn location_to_range(location: Location) -> TextRange {
+        match location {
+            Location::Offset(offset) => TextRange::offset_len(offset, 1.into()),
+            Location::Range(range) => range,
+        }
+    }
+
+    let mut errors: Vec<Diagnostic> = file
+        .errors()
+        .into_iter()
+        .map(|err| Diagnostic {
+            range: location_to_range(err.location()),
+            message: format!("Syntax Error: {}", err),
+            severity: Severity::Error,
+            fix: None,
+        })
+        .collect();
+
+    for node in file.syntax().descendants() {
+        check_unnecessary_braces_in_use_statement(file_id, &mut errors, node);
+        check_struct_shorthand_initialization(file_id, &mut errors, node);
+    }
+
+    errors
+}
+
+fn check_unnecessary_braces_in_use_statement(
+    file_id: FileId,
+    acc: &mut Vec<Diagnostic>,
+    node: &SyntaxNode,
+) -> Option<()> {
+    let use_tree_list = ast::UseTreeList::cast(node)?;
+    if let Some((single_use_tree,)) = use_tree_list.use_trees().collect_tuple() {
+        let range = use_tree_list.syntax().range();
+        let edit =
+            text_edit_for_remove_unnecessary_braces_with_self_in_use_statement(single_use_tree)
+                .unwrap_or_else(|| {
+                    let to_replace = single_use_tree.syntax().text().to_string();
+                    let mut edit_builder = TextEditBuilder::default();
+                    edit_builder.delete(range);
+                    edit_builder.insert(range.start(), to_replace);
+                    edit_builder.finish()
+                });
+
+        acc.push(Diagnostic {
+            range,
+            message: format!("Unnecessary braces in use statement"),
+            severity: Severity::WeakWarning,
+            fix: Some(SourceChange {
+                label: "Remove unnecessary braces".to_string(),
+                source_file_edits: vec![SourceFileEdit { file_id, edit }],
+                file_system_edits: Vec::new(),
+                cursor_position: None,
+            }),
+        });
+    }
+
+    Some(())
+}
+
+fn text_edit_for_remove_unnecessary_braces_with_self_in_use_statement(
+    single_use_tree: &ast::UseTree,
+) -> Option<TextEdit> {
+    let use_tree_list_node = single_use_tree.syntax().parent()?;
+    if single_use_tree.path()?.segment()?.syntax().first_child()?.kind() == SyntaxKind::SELF_KW {
+        let start = use_tree_list_node.prev_sibling()?.range().start();
+        let end = use_tree_list_node.range().end();
+        let range = TextRange::from_to(start, end);
+        let mut edit_builder = TextEditBuilder::default();
+        edit_builder.delete(range);
+        return Some(edit_builder.finish());
+    }
+    None
+}
+
+fn check_struct_shorthand_initialization(
+    file_id: FileId,
+    acc: &mut Vec<Diagnostic>,
+    node: &SyntaxNode,
+) -> Option<()> {
+    let struct_lit = ast::StructLit::cast(node)?;
+    let named_field_list = struct_lit.named_field_list()?;
+    for named_field in named_field_list.fields() {
+        if let (Some(name_ref), Some(expr)) = (named_field.name_ref(), named_field.expr()) {
+            let field_name = name_ref.syntax().text().to_string();
+            let field_expr = expr.syntax().text().to_string();
+            if field_name == field_expr {
+                let mut edit_builder = TextEditBuilder::default();
+                edit_builder.delete(named_field.syntax().range());
+                edit_builder.insert(named_field.syntax().range().start(), field_name);
+                let edit = edit_builder.finish();
+
+                acc.push(Diagnostic {
+                    range: named_field.syntax().range(),
+                    message: format!("Shorthand struct initialization"),
+                    severity: Severity::WeakWarning,
+                    fix: Some(SourceChange {
+                        label: "use struct shorthand initialization".to_string(),
+                        source_file_edits: vec![SourceFileEdit { file_id, edit }],
+                        file_system_edits: Vec::new(),
+                        cursor_position: None,
+                    }),
+                });
+            }
+        }
+    }
+    Some(())
+}
+
+#[cfg(test)]
+mod tests {
+    use test_utils::assert_eq_text;
+
+    use super::*;
+
+    type DiagnosticChecker = fn(FileId, &mut Vec<Diagnostic>, &SyntaxNode) -> Option<()>;
+
+    fn check_not_applicable(code: &str, func: DiagnosticChecker) {
+        let file = SourceFile::parse(code);
+        let mut diagnostics = Vec::new();
+        for node in file.syntax().descendants() {
+            func(FileId(0), &mut diagnostics, node);
+        }
+        assert!(diagnostics.is_empty());
+    }
+
+    fn check_apply(before: &str, after: &str, func: DiagnosticChecker) {
+        let file = SourceFile::parse(before);
+        let mut diagnostics = Vec::new();
+        for node in file.syntax().descendants() {
+            func(FileId(0), &mut diagnostics, node);
+        }
+        let diagnostic =
+            diagnostics.pop().unwrap_or_else(|| panic!("no diagnostics for:\n{}\n", before));
+        let mut fix = diagnostic.fix.unwrap();
+        let edit = fix.source_file_edits.pop().unwrap().edit;
+        let actual = edit.apply(&before);
+        assert_eq_text!(after, &actual);
+    }
+
+    #[test]
+    fn test_check_unnecessary_braces_in_use_statement() {
+        check_not_applicable(
+            "
+            use a;
+            use a::{c, d::e};
+        ",
+            check_unnecessary_braces_in_use_statement,
+        );
+        check_apply("use {b};", "use b;", check_unnecessary_braces_in_use_statement);
+        check_apply("use a::{c};", "use a::c;", check_unnecessary_braces_in_use_statement);
+        check_apply("use a::{self};", "use a;", check_unnecessary_braces_in_use_statement);
+        check_apply(
+            "use a::{c, d::{e}};",
+            "use a::{c, d::e};",
+            check_unnecessary_braces_in_use_statement,
+        );
+    }
+
+    #[test]
+    fn test_check_struct_shorthand_initialization() {
+        check_not_applicable(
+            r#"
+            struct A {
+                a: &'static str
+            }
+
+            fn main() {
+                A {
+                    a: "hello"
+                }
+            }
+        "#,
+            check_struct_shorthand_initialization,
+        );
+
+        check_apply(
+            r#"
+struct A {
+    a: &'static str
+}
+
+fn main() {
+    let a = "haha";
+    A {
+        a: a
+    }
+}
+        "#,
+            r#"
+struct A {
+    a: &'static str
+}
+
+fn main() {
+    let a = "haha";
+    A {
+        a
+    }
+}
+        "#,
+            check_struct_shorthand_initialization,
+        );
+
+        check_apply(
+            r#"
+struct A {
+    a: &'static str,
+    b: &'static str
+}
+
+fn main() {
+    let a = "haha";
+    let b = "bb";
+    A {
+        a: a,
+        b
+    }
+}
+        "#,
+            r#"
+struct A {
+    a: &'static str,
+    b: &'static str
+}
+
+fn main() {
+    let a = "haha";
+    let b = "bb";
+    A {
+        a,
+        b
+    }
+}
+        "#,
+            check_struct_shorthand_initialization,
+        );
+    }
+}